Turbomachine Casing Assembly with Resilient Energy Absorption
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Solution Overview
Problem
Conventional turbomachine casing assemblies suffer from costly and time-consuming maintenance due to severe damage from fan blade interactions, ice impacts, and Foreign Object Damage, which affect aerodynamic performance and lead to premature wear of fan blades and liners.
Innovation Solution
A turbomachine casing assembly featuring a movable first casing portion connected to a second casing portion via resilient elements such as springs or an inflatable member, allowing radial deflection to absorb energy during interactions and reduce damage, with a simplified structure that eliminates the need for an outer honeycomb, enabling cost and weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fan track liner is bonded directly to the fan case with a rigid aluminium honeycomb structure, then the liner is positioned correctly and supported to prevent damage during ice impacts, but the liner suffers severe damage from fan blade interactions requiring costly and time-consuming repair or replacement
Solution Approach 1:
The patent applies the dynamics principle by replacing the rigid aluminium honeycomb structure with a resilient element that can dynamically deflect and absorb energy during fan blade interactions. The resilient element allows the liner to move radially outward when impacted by a fan blade, reducing the transmission of harmful forces to the liner and underlying structure, thereby minimizing damage and reducing maintenance requirements.
Solution Approach 2:
The patent applies beforehand cushioning by positioning the resilient element between the liner and the fan case before any impact occurs. This resilient element acts as a pre-positioned energy-absorbing cushion that activates during fan blade interactions, ice impacts, or FOD events, protecting the liner and structure from severe damage before harmful forces can cause extensive damage.
2Reliability
If an aluminium honeycomb structure is used to position the attrition liner and accommodate the rotor assembly, then the liner is supported and positioned correctly, but the structure is complex and heavy
Solution Approach 1:
The patent applies the taking out principle by removing the complex aluminium honeycomb structure entirely from the design. The resilient element is integrated directly into the fan case or liner assembly, eliminating the need for a separate honeycomb structure while maintaining the necessary support and positioning functions. This simplifies the overall device complexity and reduces weight.
3Strength
If the fan case thickness is increased to prevent machining during subsequent run-on after a blade release, then the casing is more robust, but the weight and complexity of the assembly increases
Solution Approach 1:
The resilient element serves as a beforehand cushioning mechanism that absorbs energy from blade releases and FOD impacts before these forces can cause extensive damage to the fan case. This energy absorption capability allows the fan case to be designed with reduced thickness while maintaining adequate protection, thereby reducing weight without compromising strength.
Solution Approach 2:
The patent applies parameter changes by utilizing the resilient element's ability to change its mechanical properties (deflection, energy absorption) in response to different impact conditions. This dynamic response allows the system to protect against severe impacts with a thinner case design, as the resilient element compensates for the reduced structural margin.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution minimizes damage to the attrition liner and underlying structure, reduces maintenance costs, and enhances aerodynamic performance by absorbing energy from fan blade interactions and ice impacts, while allowing for tunable containment behavior and reduced fan case thickness.
Implementation Method 1
The turbomachine casing assembly is further provided with a resilient element arranged so as to resist movement of the first casing portion with respect to the second casing portion
Implementation Method 2
The resilient element may be in the form of an inflatable member
Data Source
Figure 1
Figure 2a~3
Figure 4a~4b
AI summary
A turbomachine casing assembly comprises a first casing portion for at least partially encasing one or more rotating aerofoil structures of a turbomachine and a second casing portion; the first casing portion being movable with respect to the second casing portion.